Preview at WWDC likely in June, followed by September launch.
Apple Seeds Fourth Beta of iOS 9.3.2 to Developers and Public Beta Testers
iOS 9.3.2 beta 4 can be downloaded over-the-air using the beta configuration profile or through the Apple Developer Center.
iOS 9.3.2, as an 9.x.x update, appears to be minor in scale, focusing on bug fixes and performance improvements. iOS 9.3.2 appears to fix a major Game Center bug that has plagued some iOS users for months and it introduces support for using Night Shift and Low Power Mode simultaneously.
The first three betas of iOS 9.3.2 have not included any significant outward-facing changes, but we will update this post with any new features found in the fourth beta.